Radar Of Radio Detection And Multiple Classification And Sub Systems Used For Processing

1699 Words Aug 27th, 2016 7 Pages
II. RADAR
Radio Detection and Ranging (RADAR) is a sensor used in the automotive domain to derive speed and distance information. Now we will discuss on the principle of working, its classification and sub-systems used for processing. Currently we used frequency modulated continuous wave (FMCW) RADARs and so this type will be elaborated here.
A. Principle
The RADAR sensor measurements are mainly based on three principles: time-of-flight, Doppler Effect and Frequency Modulated Continuous Wave (FMCW).
1) Time-of-Flight
Distance measurement is basically based on the principle of time-of-flight, which is that the time between the transmitted and received signal is proportional to the distance between the objects. 2) Doppler Effect
Frequency of the received signal is offset by a positive frequency factor when the source and the target are approaching towards each other and by a negative factor when they are moving away from each other.
3) Frequency Modulated Continuous Wave (FMCW) The transmission is a continuously increasing frequency signal, and then at the maximum frequency, abruptly begins to continuously decrease in frequency until it reaches the minimum frequency. This cycle then repeats. The frequency over time looks like a “saw tooth wave”.
As you can see from Fig. 3, the horizontal delay between the transmitted and the received signals is the time delay used for range measurement and the vertical shift is the Doppler Shift used for velocity calculations. But…
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